Two important attributes of any high performance current driver are its output impedance and its output offset current. Often the goal is to design a current driver with a high output impedance along with very low offset current. It is fairly straightforward to achieve the first goal through the use of cascoded or resistor de-generated FET devices to create very high output impedance current sources. However, the generation of a high output impedances typically results in the creation of output offset currents due to a mismatch between the D.C. bias currents of the upper and lower current sources that drive the output. The task of reducing TI-28914 this mismatching of currents involves both the careful layout of circuit devices, as well as the use of some additional circuitry to both measure and correct for the offset current. Typical design approaches used to achieve this "zeroing out" of offset currents tend to add a considerable amount of "circuit overhead" relative to the overall current driver topology.